Free Printable Thermochemistry

Worksheets

Thermochemistry

Total questions: 36

Worksheet time: 1hrs 24mins

Name

Class

Date

What are the two units for Heat?

cal and joules

cal and grams

joules and celcius

there is only one

energy in endothermic reactions are

released

ended

absorbed

energy in exothermic reactions are

released

absorbed

Heat flows from _______ to ______ objects

cooler to warmer

warmer to warmer

warmer to cooler

cooler to cooler

Heat is measured in

joules

grams

degrees celcius

q stands for which variable

heat

mass

specific heat

change in temperature

The variable C stands for what

heat

mass

specific heat

change in temperature

For the formula:
Q= m c ∆T
The units for specific heat are:

g /J C

°C/g J

kJ/g

J/g°C

A sample of iron receives 50.J of heat energy that raises the temperature of the iron 25.0°C. If iron has a specific heat of .10 J/g°C, what is the mass of the iron sample?

25g

30g

20g

50g

10.

If 238 J of heat is absorbed by a sample of metal with a mass of 40.7 g, and it raises the temperature from 20.0°C to 32.4°C, what is the specific heat capacity of the metal? (show your work)

2.34 J/g°C

0.472 J/g°C

6.13 J/g°C

0.163 J/g°C

11.

Is Evaporation endothermic or exothermic?

endothermic

exothermic

12.

Is Freezing endothermic or exothermic?

endothermic

exothermic

13.

Energy can not be created or destroyed, it can only be transferred refers to the....

law of conservation of energy

law of conservation of mass

life facts

law of conservation of chemistry

14.

A person warming themselves from a fire is

endothermic

exothermic

15.

A 500g piece of Aluminum has a temperature of 7 degrees. What is the heat energy produced? Specific heat of Aluminum is .900 J/gC.

3000 J

3000 g

3150 J

3150 g

16.

When 1500J of energy is lost from a 120 gram object, the temperature decreased from 45 degrees C to 40 degrees C. What is the specific heat of the object?

2.5 J/gC

1.5 J

12.5 Cal/gC

15 J/gC1

17.

A liquid with a specific heat of 1.9 J/gC has 4750 J of energy added to it. The temperature changed from 20 degrees C to 30 degrees C, what is the mass of the liquid?

250 cal

2500cal

250 g

2500 cal

18.

Refer the the following question:

2N₂ + 3H₂ --> 2NH₃ + 46 kJ

How much energy would be produced if only 1 mol of nitrogen was reacted?

(Remember, coefficient of 1 = 1 mole)

92 kJ

0.143 kJ

23 kJ

15 kJ

19.

How much energy must be used to produce 4.75 mol of gaseous water?

H₂O (l) + 44.0 kJ --> H₂O (g)

(Remember, coefficient of 1 = 1 mole)

207 kJ

9.36 kJ

206.8 kJ

9.362 kJ

20.

4 PCl₅ + 3438 kJ --> P₄ + 10 Cl₂

How much energy is required to produce each mole of chlorine?

(Remember, coefficient of 1 = 1 mole)

687.6 kJ

859.5 kJ

343.8 kJ

245.8 kJ

21.

H₂ + Cl₂ --> 2 HCl + 1845 kJ
Is this reaction endothermic or exothermic?

Endothermic

Exothermic

22.

The specific heat of mercury is 0.140 J/g⋅K. How many joules of energy are needed to warm 4.52 g of mercury from 24.6^oC to 27.1^oC?

0.632 J

13.8 J

3.96 J

1.58 J

23.

300 mL of water at 95 ºC are added to 700 mL of water at 62.8 ºC. What is the final temperature of the full liter of water?

50 ºC

85.6 ºC

72.5 ºC

94.2 ºC

24.

What is true of this reaction?

Equal amounts of energy were released and absorbed

The reaction released more energy than it absorbed

The reaction absorbed more energy than it released

25.

What is true of the reaction described below?
Br₂+ Cl₂ + 30.0 J of energy → 2BrCl

It is exothermic because energy was released.

It is endothermic because energy is absorbed.

It is exothermic because energy is absorbed.

It is endothermic because energy is released.

26.

What is the potential energy of the reactants? The energy readings are top 103, middle 45 and bottom 10

10 kJ

45 kJ

103 kJ

58 kJ

27.

What is the potential energy of the products? The energy readings are top 103, middle 45 and bottom 10

10 kJ

45 kJ

103 kJ

58 kJ

28.

If a 40.0 g sample of metal cools from 80.0°C to 20.0°C and loses 1060 J of energy, what is the specific heat of the metal?
C=q/mΔT

-0.442 J/g°C

0.442 J/g°C

0.00142 J/g°C

0.000629 J/g°C

29.

The specific heat of silver is 0.24 J/g·°C. How many joules of heat must be added to an 83.6 g silver block to raise its temperature by 9.0°C?
q=mCΔT

0.00032 J

0.45 J

180 J

39 J

30.

The equation for heat transfer is $\Delta Q\ =\ m\times c\times\Delta T$ Using this equation, figure out how much heat is required to warm up 2.0 kg of water from 20 degree C to 100 degrees C. Conveniently, the specific heat capacity of water is 1 cal/gram/degree C

40,000 cal

160,000 cal

20,000 cal

80,000 cal

31.

The equation for heat transfer is $\Delta Q\ =\ m\times c\times\Delta T$ Using this equation, figure out how much heat is released when 100 grams of olive oil cool by 40 degrees C. The specific heat capacity of olive oil is c = 0.5 calories/gram/degree C.

40 cal

100 cal

1000 cal

2000 cal

32.

If a chemical reaction is EXOTHERMIC...

The solution will increase in temperature

The solution will decrease in temperature

There will be no change

33.

If a chemical reaction is ENDOTHERMIC...

The solution will increase in temperature

The solution will decrease in temperature

There will be no change

34.

Use the H_f values in the table below to answer questions a and b about the following reaction.

CO_2(g) + N_2(g) ⟶ NO_(g) + CO_(g) ΔH = ?

Formula kJ/mol

CO(g)= -110

CO2(g) =-394

NO(g) =90

N₂(g)= 0

a) Calculate Hrxn for the reaction.

370kJ/mol

374kJ/mol

333kJ/mol

335KJ/mol

35.

Calculate the enthalpy of reaction (ΔH).

4CO_{2 (g)} + 6H₂O _(g) → 2C₂H_{6 (g)} + 7O_{2 (g)}

ΔH_f^o [CO_2(g)] = -393.5 kJ

ΔH_f^o[H₂O_(g)] = -241.8 kJ

ΔH_f^o [C₂H_6(g)] = -84.7 kJ

550.647 KJ/mol

2855.584 KJ/mol

-550.647 KJ/mol

-2855.584 KJ/mol

36.

The standard enthalpy of formation of NH₃ (g) at 298K is -46 kJmol^-1. What is the enthalpy change of the following reaction?

2NH₃(g) ---> N₂(g) + 3H₂(g)

-46 kJmol^-1

+92 kJmol^-1

-92 kJmol^-1

+46 kJmol^-1

Reset

Thermochemistry

Total questions: 36

Worksheet time: 1hrs 24mins

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